Strings in C#

String is nothing but a collection of characters be it collection of alphabets, alphanumeric or include special symbols. String is always enclosed within double quotes. Examples of String are: “Hello”,”Hello World!”,”P@ssw0rd2018″ etc.

We can do lots of manipulation on these string values. System.String provides a number of methods that we can use to manipulate these values. Lets see how to do that. I am creating a Console Application StringDemo.

Assign value to a string variable:

String value = "Hello World";

Concat()
We can concatenate two or more string values in one using plus (+) sign or using
Concat function.

String val1 = "My name is";
String val2 = "David";
String val3 = "Miller";
String val4 = val1 + " " + val2 + "!";
Console.WriteLine("Concatenated Value using + sign: " + val1 + " " + val2);
Console.WriteLine("Value of val4: " + val4);
String val5 = String.Concat(val1, " ",val2, " ", val3);
Console.WriteLine("Concatenated value using Concat function: " + val5);

Below is the result of the above code:

Length
Length is used to calculate the number of characters that are there in the string. It also counts the space characters. Result of below code is:

String value = "Hello World";
Console.WriteLine("Length of " + value + "is: " + value.Length);

Below is the result of the above code:

Compare()
C# is case-sensitive. Hence Hello is different from hello. Compare function is used to compare two strings. This function returns an integer value. If this returns 0, he values are same. If this returns 1, values are different. Below is the sample code:

String val1 = "Hello";
String val2 = "Hello";
String val3 = "hello";
int result = String.Compare(val1, val3);
int result1 = String.Compare(val1, val2);
int result2 = String.Compare(val1, val3, true);
Console.WriteLine("Comparison of Hello and hello: " + result);
Console.WriteLine("Comparison of Hello and Hello: " + result1);
Console.WriteLine("Comparison of Hello and hello, ignored the case: " + result2);

Below is the result of the above code:

Contains()
This method determines whether a string contains a specified substring. It will return a bool value, either true or false.
Below is a sample code:

String val = "Hello World";
bool result = val.Contains("Wor");
bool result1 = val.Contains("Hi");
Console.WriteLine("Hello World contains Wor? " + result);
Console.WriteLine("Hello World contains Hi? " + result1);

Below is the result of the above code:

Insert()
Insert() method inserts a specified string within a string at a given index. The index starts with 0.

String original = "HelloWorld!";
Console.WriteLine("The original string: '{0}'", original);
String updated = original.Insert(5, " ");
Console.WriteLine("The modified string: '{0}'", updated);
String updated1 = original.Insert(5, " Big ");
Console.WriteLine("The modified string: '{0}'", updated1);

Below is the result of above code:

PadLeft(), PadRight()
These methods are used to pad a character either left or right of a string.
Below is the sample code:

String name = "David";
char char1 = '*';
Console.WriteLine(name.PadLeft(15, char1));
Console.WriteLine(name.PadLeft(3, char1));
Console.WriteLine(name.PadRight(15, char1));
Console.WriteLine(name.PadRight(6, char1));

Below is the output of above code:

Insert(), Remove(), Replace()
Insert() method is used to insert a given string into another string at a specific index.
Remove() method is used to delete a specified number of characters from a specified string.
Replace() method is used to replace all occurrences of a specified character with another character in a specified string.
Below is the sample code for above method:

String str = "Hello World!";
Console.WriteLine("str = " + str);
Console.WriteLine("str.Insert(6, \"Hi \") : " + str.Insert(6, "Hi "));
Console.WriteLine("str.Remove(7,2) : " + str.Remove(7,2));
Console.WriteLine("str.Remove(7) : " + str.Remove(7));
Console.WriteLine("str.Replace(7,2) : " + str.Replace('l','*'));
Console.WriteLine("str.Replace(\"ll\",\"12\") : " + str.Replace("ll","12"));

Below is the result of above code:

Split()
This method is used to split a string in an array.
Below is the sample code for above method:

String str = "Orange,Yellow,Red,Green,Blue";
String[] colors=str.Split(',');
Console.WriteLine("str: " + str);
Console.WriteLine("Split character: \',\'");
Console.WriteLine();
Console.WriteLine("Result after splitting the string using \"str.Split(\',\')\"");
foreach(String s in colors)
{
    Console.WriteLine(s);
}

Below is the result of the above code:

Trim()
Trim() removes all the leading and trailing white-space characters from the string.
Below is the sample code:

String str = " Hello World ";
Console.WriteLine("str: " + str + "!");
Console.WriteLine("str.Trim(): " + str.Trim() + "!");

Below is the result of above code:

ToUpper(), ToLower()
ToUpper() is used to convert the complete string in upper-case.
ToLower() is used to convert the complete string in lower-case.
Below is the sample code:

String str = "Hello World!";
Console.WriteLine("str: " + str);
Console.WriteLine("str.ToUpper() : " + str.ToUpper());
Console.WriteLine("str.ToLower() : " + str.ToLower());

Below is the output of above code: